Quantitative structure-property relationships on photolysis of PCDD/Fs adsorbed to spruce (Picea abies (L.) Karst.) needle surfaces under sunlight irradiation

By partial least squares (PLS) regression, quantitative structure-property relationship (QSPR) models were developed for photolysis half-life (t1/2) of PCDD/Fs and PAHs sorbed to spruce (Picea abies (L.) Karst.) needle surfaces and irradiated by sunlight. Quantum chemical descriptors computed by PM3 Hamiltonian were used predictor variables. PLS analysis for the PCDDs and PAHs respectively resulted in no correlation by our statistical methods. The cross-validated Qcum2 value for the optimal QSPR model of PCDFs is 0.722, indicating a good predictive ability for log t1/2 of PCDFs adsorbed to spruce needle surfaces. The QSPR results show that the number of chlorine atoms bonded to the parent structure and (ELUMO − EHOMO)2 has a dominant effect on t1/2 values of PCDFs. Increasing the number of chlorine atoms and (ELUMO − EHOMO)2 values leads to increase of log t1/2 values of PCDFs.